package com.demo.interpreter22;

import java.util.Stack;

public class Calculator{
    private String statement;
    private Node node;
    
    public void build(String statement){
        Node left=null,right=null;
        Stack stack=new Stack();
        
        String[] statementArr=statement.split(" ");
        
        for(int i=0;i<statementArr.length;i++){    
            if(statementArr[i].equalsIgnoreCase("*")){
                left=(Node)stack.pop();
                int val=Integer.parseInt(statementArr[++i]);
                right=new ValueNode(val); 
                stack.push(new MulNode(left,right));
            }
            else if(statementArr[i].equalsIgnoreCase("/")){
                left=(Node)stack.pop();
                    int val=Integer.parseInt(statementArr[++i]);
                    right=new ValueNode(val); 
                stack.push(new DivNode(left,right));                
            }
            else if(statementArr[i].equalsIgnoreCase("%")){
                left=(Node)stack.pop();
                    int val=Integer.parseInt(statementArr[++i]);
                    right=new ValueNode(val); 
                stack.push(new ModNode(left,right));               
            }
            else{
                stack.push(new ValueNode(Integer.parseInt(statementArr[i])));
            }
        }
        this.node=(Node)stack.pop();
    }
    
    public int compute(){
        return node.interpret();
    }
}